# GPT-5.6 Sol vs Grok 4.5

> GPT-5.6 Sol is the stronger model overall, scoring 64.4 to 55.0 on the Noometry Index. Grok 4.5 costs 2.7× less per token, which makes it the better buy when GPT-5.6 Sol's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/gpt-5-6-sol-vs-grok-4-5
- Last updated: 2026-10-10
- Shared benchmarks: 52

## Summary

- They share 52 benchmarks with published results for both. GPT-5.6 Sol scores higher in 10 categories and Grok 4.5 in 0 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in math, where GPT-5.6 Sol leads 85.5 to 60.7.
- The biggest single-benchmark swing is FrontierMath Tier 4: 82.9% for GPT-5.6 Sol and 24.4% for Grok 4.5.
- Grok 4.5 is cheaper at $2 / $6 per million input/output tokens, against $4 / $20 for GPT-5.6 Sol.
- GPT-5.6 Sol accepts more context: 1.05M tokens versus 500K.

## Snapshot

| | GPT-5.6 Sol | Grok 4.5 |
|---|---|---|
| Provider | OpenAI | xAI |
| Noometry Index | 64.4 | 55.0 |
| Rank | 6 | 22 |
| Context | 1.05M | 500K |
| Input $/M | $4 | $2 |
| Output $/M | $20 | $6 |
| Weights | Proprietary | Proprietary |

## Coding

- GPT-5.6 Sol: 61.1 (#7)
- Grok 4.5: 51.7 (#34)

| Benchmark | GPT-5.6 Sol | Grok 4.5 |
|---|---|---|
| DeepSWE | 72.7% | 53.8% |
| FrontierCode | 47.5% | 42.4% |
| LMArena WebDev | 1619 | 1552 |
| SciCode | 57.1% | 54.1% |
| WeirdML | 89.4% | 46.4% |
| LMArena Coding | 1493 | 1473 |
| ALE-Bench | 2,177 | 1,309 |
| CursorBench | 41.7% | — |
| FrontierSWE | 32.2% | — |
| MirrorCode | 20% | — |

## Agentic & Tool Use

- GPT-5.6 Sol: 50.2 (#7)
- Grok 4.5: 44.4 (#15)

| Benchmark | GPT-5.6 Sol | Grok 4.5 |
|---|---|---|
| APEX-Agents | 51.4% | 56.2% |
| τ²-bench Banking | 46.9% | 47.9% |
| PostTrainBench | 36.2% | 23.4% |
| GBAEval | 52.6% | 65.4% |
| GDP.pdf | 30.7% | 14% |
| LMArena Search | 1257 | 1213 |
| Vending-Bench 2 | 9,619 | 3,887 |
| OSWorld 2.0 | 27.3% | — |
| BALROG | 60% | — |

## Reasoning

- GPT-5.6 Sol: 74.7 (#6)
- Grok 4.5: 56.0 (#23)

| Benchmark | GPT-5.6 Sol | Grok 4.5 |
|---|---|---|
| ARC-AGI-2 | 92.5% | 52.6% |
| SimpleBench | 71.7% | 70% |
| Kagi LLM Benchmark | 67% | 83.5% |
| NYT Connections (extended) | 93.8% | 79.9% |
| ARC-AGI-1 | 97.5% | 87.2% |
| CritPt | 32.3% | 15.4% |
| Chess Puzzles | 64% | 36% |
| LMArena Hard Prompts | 1481 | 1462 |
| DTBench | 96% | 96.5% |
| LMCA | 59.2% | 45.2% |
| Surface Evolver Bench | 93.1% | 74.4% |
| Epoch Capabilities Index | 161.99 | 154.02 |
| EnigmaEval | 37.1% | — |
| EBR-Bench | 44.8% | — |
| Mystery Game Puzzles | 58% | — |
| Bench to the Future 3 | 0.14 | — |

## Math

- GPT-5.6 Sol: 85.5 (#7)
- Grok 4.5: 60.7 (#29)

| Benchmark | GPT-5.6 Sol | Grok 4.5 |
|---|---|---|
| FrontierMath (Tiers 1-3) | 89.1% | 57.2% |
| FrontierMath Tier 4 | 82.9% | 24.4% |
| OTIS Mock AIME 2024-2025 | 100% | 97.8% |
| ProofBench | 83% | 31% |
| LMArena Math | 1472 | 1457 |
| FrontierMath Erdős | 0% | — |

## Knowledge

- GPT-5.6 Sol: 64.3 (#16)
- Grok 4.5: 62.3 (#21)

| Benchmark | GPT-5.6 Sol | Grok 4.5 |
|---|---|---|
| GPQA Diamond | 93.5% | 93.4% |
| SimpleQA Verified | 69.7% | 48.3% |
| LMArena Expert | 1517 | 1466 |
| Vectara Hallucination Rate | 12.4% | — |

## Multimodal

- GPT-5.6 Sol: 48.9 (#8)
- Grok 4.5: 37.8 (#63)

| Benchmark | GPT-5.6 Sol | Grok 4.5 |
|---|---|---|
| LMArena Vision | 1281 | 1287 |
| Blueprint-Bench 2 | 33.6% | 27.3% |
| Furniture Assembly | 56.7% | 22.5% |
| LMArena Document | 1483 | 1452 |

## Multilingual

- GPT-5.6 Sol: 55.4 (#32)
- Grok 4.5: 54.5 (#43)

| Benchmark | GPT-5.6 Sol | Grok 4.5 |
|---|---|---|
| LMArena Non-English | 1450 | 1439 |
| LMArena Chinese | 1523 | 1497 |
| LMArena French | 1475 | 1458 |
| LMArena German | 1476 | 1448 |
| LMArena Japanese | 1475 | 1425 |
| LMArena Korean | 1434 | 1402 |
| LMArena Russian | 1466 | 1447 |
| LMArena Spanish | 1449 | 1452 |

## Instruction Following

- GPT-5.6 Sol: 77.8 (#16)
- Grok 4.5: 76.3 (#45)

| Benchmark | GPT-5.6 Sol | Grok 4.5 |
|---|---|---|
| LMArena Instruction Following | 1480 | 1446 |

## Long Context

- GPT-5.6 Sol: 45.3 (#42)
- Grok 4.5: 44.8 (#54)

| Benchmark | GPT-5.6 Sol | Grok 4.5 |
|---|---|---|
| LMArena Longer Query | 1479 | 1463 |

## Writing & Preference

- GPT-5.6 Sol: 73.5 (#12)
- Grok 4.5: 65.9 (#40)

| Benchmark | GPT-5.6 Sol | Grok 4.5 |
|---|---|---|
| LMArena Text | 1456 | 1448 |
| LMArena Creative Writing | 1450 | 1442 |
| EQ-Bench Creative Writing | 1972 | 1579 |
| LMArena Multi-Turn | 1456 | 1457 |
| EQ-Bench 4 | 1250 | — |

## FAQ

### Is GPT-5.6 Sol better than Grok 4.5?

GPT-5.6 Sol is the stronger model overall, scoring 64.4 to 55.0 on the Noometry Index. Grok 4.5 costs 2.7× less per token, which makes it the better buy when GPT-5.6 Sol's lead doesn't matter for your workload.

### Which is cheaper, GPT-5.6 Sol or Grok 4.5?

Grok 4.5 is cheaper. It lists at $2 per million input tokens and $6 per million output tokens; GPT-5.6 Sol lists at $4 and $20.

### Is GPT-5.6 Sol or Grok 4.5 better for coding?

GPT-5.6 Sol scores higher on coding benchmarks: 61.1 versus 51.7 in the Noometry coding category.

### Which has the bigger context window?

GPT-5.6 Sol does, with 1.05M tokens against 500K.

### How many benchmarks do GPT-5.6 Sol and Grok 4.5 share?

52 benchmarks have published results for both models. GPT-5.6 Sol has 64 scored results on Noometry and Grok 4.5 has 52.